Have you ever needed to remove and replace the first three letters of a file name across hundred of files. Or remove a specific character series from the middle of hundreds of file names in folders and subfolders.

I've done this and more using Rename Master. Except when I first fired it up I didn't realize what it could do. Its interface did not inspire confidence. I didn't notice the recursive feature. The tree navigation pane was not visible. And it was not until I came back to it weeks later that I realized what a powerhouse this is. But I had to be willing to sit down and learn the program by mousing over everything and popping into every choice. Once I did that I was able to do renaming scenarios I previously thought were impossible.

It also allows you to preview what the renames will look like to all the files you are renaming, and even undo them after the fact. These two features are invaluable if you are doing complex changes on a batch of hundreds of dissimilar filenames.